Design Patterns design recommended
Result/Either Pattern
The Result/Either Pattern provides explicit error handling using discriminated unions instead of exceptions. Enables composable, type-safe error handling with map/flatMap operations.
- Difficulty
- intermediate
- Read time
- 1 min read
- Version
- v1.0.0
- Confidence
- established
- Last updated
Quick Reference
Result Pattern: Return Result<T, E> instead of throwing exceptions. Ok(value) for success, Err(error) for failure. Benefits: explicit error handling, type-safe, composable (map, flatMap). Use for expected failures (validation, not found). Keep exceptions for unexpected/unrecoverable errors.
Use When
- Expected error cases (validation, not found)
- Composing multiple fallible operations
- API boundaries where errors should be explicit
- Functional programming style
Skip When
- Truly exceptional circumstances
- Simple scripts where exceptions are fine
- Framework requires exceptions (e.g., Express middleware)
Result/Either Pattern
The Result/Either Pattern provides explicit error handling using discriminated unions instead of exceptions. Enables composable, type-safe error handling with map/flatMap operations.